[Arkadir]

A few years ago, I came up with a similar proposal, though more specifically aimed at making callbacks easier to manage. It was a simple syntax extension, as opposed to new semantics for the language.

You would write this:

    var! x = expression;
    statement;
    statement;

And JavaScript would parse it as:

    return expression.then(function(x) {
      statement;
      statement;
    });

This is obviously shamelessly pilfered from monadic syntax 'let!' in F#, and my own 'let!' extension in OCaml.